Integrated circuits typically have dedicated interface circuits to communicate with other integrated circuits and other systems. Some dedicated interface circuits employ current mode transmitters that drive currents between integrated circuits. Signals that travel from one integrated circuit to another are becoming faster and faster.
As signal speeds increase, the effect of imperfect “channels” also increases. A “channel,” for the purposes of this description, is any medium that the signal passes through. For example, a channel may include printed circuit board traces or wires routed between integrated circuits. One possible effect of an imperfect channel is frequency-dependent attenuation of signal amplitudes. In general, when the signal amplitude is attenuated as a function of frequency, the signal becomes smaller as the speed increases. When the signal gets too small, communications between integrated circuits may become unreliable.
One known method for compensating for frequency-dependent attenuation is the use of pre-emphasis at the transmitter. Pre-emphasis at the transmitter involves cutting the signal after a signal level change to cause the signal to achieve a higher voltage at a signal change. However, pre-emphasis reduces eye height of the signal.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some embodiments described herein may be practiced.